DdrB stimulates single-stranded DNA annealing and facilitates RecA-independent DNA repair in Deinococcus radiodurans

Guangzhi Xu, Huiming Lu, Liangyan Wang, Huan Chen, Zhenjian Xu, Yihuai Hu, Bing Tian, Yuejin Hua

Research output: Contribution to journalArticle

35 Scopus citations


The bacterium Deinococcus radiodurans can survive extremely high exposure to ionizing radiation. The repair mechanisms involved in this extraordinary ability are still being investigated. ddrB is one gene that is highly up-regulated after irradiation, and it has been proposed to be involved in RecA-independent repair in D. radiodurans. Here we cloned, expressed and characterized ddrB in order to define its roles in the radioresistance of D. radiodurans. DdrB preferentially binds to single-stranded DNA. Moreover, it interacts directly with single-stranded binding protein of D. radiodurans DrSSB, and stimulates single-stranded DNA annealing even in the presence of DrSSB. The post-irradiation DNA repair kinetics of a ddrB/recA double mutant were compared to ddrB and recA single mutants by pulsed-field gel electrophoresis (PFGE). DNA fragment rejoining in the ddrB/recA double mutant is severely compromised, suggesting that DdrB-mediated single-stranded annealing plays a critical role in the RecA-independent DNA repair of D. radiodurans.

Original languageEnglish (US)
Pages (from-to)805-812
Number of pages8
JournalDNA Repair
Issue number7
Publication statusPublished - Jul 1 2010



  • DdrB
  • Deinococcus radiodurans
  • RecA-independent DNA repair
  • SSA

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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